Gaseous discharge tube and method of producing same



c. R. RUSE 2,215,441

GASEOUS DISCHARGE TUBE AND METHOD OF PRODUCING SAME I Sept. 17, 1940.

Original Filed April 14, I938 Qwuwvbo'b Car/ Ruse Patented Sept. 17, 1940 UNITED STATES GASEOUS DISCHARGE TUBE AND METHOD F PRODUCING SAME Carl R. Ruse, Toledo,

Lights, Inc., Toledo, Ohio,

Ohio

Original application Ohio, assignor to Plastic a corporation of April 14, 1938, Serial No. Divided and this application May 29,

1939, Serial No. 276,336

Claims.

This invention, a division of my copending application, relates to method and apparatus for producing signs and more particularly to improvements in. the visibility in gaseous discharge or conductor tubes.

An object of the invention is amethod and means to provide maximum visibility of the indication of a gaseous discharge tube during lumi- .l0 nous or night time operation and day time or nonluminous periods without the use of reflecting means or contrasting backgrounds;

Another object of the invention is the provision of an electric sign wherein a visual indication of a color characteristic is imparted when the sign becomes illuminated by the conduction oi electricity through a rare gas and a different color characteristic is produced when no luminosity is present.

9 Another object of the invention is the provision of a sign having means for giving a visual indication of one color characteristic and emitting when illuminated difiused light of another color characteristic.

.5 Another object of the invention resides in the provision of a material capable of diffusing light rays passing therethrough providing a uniform.

distribution of light without objectionable glare.

Still another object of the invention is the provision of composite translucent means comprising materials having different color characteristics and different light transmitting values.

Another object of the invention is the provision of an electric sign wherein the envelope is of contour to give a predetermined indication and is constructed of frangible material and coated with a material having light diffusing characteristics whereby when the sign is energized the envelope visually appears to be the source of illumination. Still another object of the invention is the provision of an envelope for a gas filled sign fabricated of materials having different color characteristics and different light transmitting values.

visual indication when the luminant is not energized.

Another object of the invention includes the method of coating a gaseous discharge tube by 55 covering the envelope with a suitable covering Serial No. 202,021, filed April 14, 1938,

Still another object of the invention is the having non-current-conducting' characteristics and which has a suitable color light diffusing pigment;

The invention also contemplates a method of applying to the outer surface of a gaseous discharge tube a covering having electrical insulating properties and which is not affected by high temperatures.

Further objects and advantages are within the scope of this invention such as relate to the arrangement, operation and function of the related elements of. the structure, to various details of construction and to combinations of parts, elements per se, and to economies of manufacture and numerous other features as will be apparent from a consideration of the specification and drawing of a form of the invention, which may be preferred, in which:

Figure l, is an elevational view of a sign utilizing a tube containing a gas which is rendered luminescent by high tension current passing through the gas within the tube;

Figure 2 is a sectional view through a tube of the sign structure of my invention, the view being taken on the line 2-2 of Figure l;

Figure 3 is an isometric view of a portion, of

tion. I

In the form of the invention of Figure l, which illustrates a typical sign utilizing gas which is rendered luminescent by the passage of electric current, the arrangement consists of a tube H1, in the illustration the same being bentto the configuration of a typical sign formed of the letters G and O, the connecting portion or cross-over ii of the tube Ill and the portions of the tube l3 and I4 which are connected to the current supply are coated with opaque paint or suitable coating to render them substantially non-luminescent, thus emphasizing the sign proper. The ends of the tube l5 and I6 contain suitable electrodes l1 and it which are connected to current supply wires l9 and 20, the latter being fused or sealed into the extremities of the tube.

In the fabrication of gaseous discharge tube signs, the tube or envelope is preferably made of a frangible material such as, for example, glass and especially lead-glass is employed as it is not brittle and may be easily bent under the heat of a gas flame to configurations of advertising signs.

The gas within the tube may be any inert gas as, for example, neon, krypton, argon, or the like, which will be rendered luminescent by the passage of high tension current through thetube which has been attributed to electronic and ionic a tube embodyinga modified form of the inven-,

interchange commonly identified as electron-ion combination or bombardment. The color characteristic of such light so given off by the gas depends upon the particular gas used in the tube. For example, neon gas emits a light having high red color characteristics, while other gases so used having different color characteristics. Signs of this character made of substantially clear or transparent glass tubing have little or no advertising value when they are not rendered luminescent by passing current therethrough, and in order that they may have an advertising value in the day time, it is essential that they be illuminated by energizing the gas with a high tension electric current, which increases the cost of operation. I have also found that signs of this character have an attendant apparent glare or reflection, which does not render the sign distinctive and clear andgreatly depreciates its visibility from a distance. I have found that by coating the effective sign indicating portion of the tube 10 with a covering which suitable heat.

has the faculty of diffusing substantially uniform the light emanating from the luminiscent gas, such coating having a color characteristic which imparts to the sign distinctive utility in the day time without the necessity of expenditure of current to render the sign luminescent. I have also found that a coating which will diffuse the light renders such sign more distinctive to a degree as such tube or envelope coated according to my invention appears to constitute a complete or enlarged source of light as compared with a transparent glass tube, which makes the sign understandably visible from a much greater distance than has been heretofore possible, as the glare normally attendant with the use of transparent glass tubing has been eliminated, and the visual appearance of the tube enlarged.

To produce a sign of the character of my invention, it is desirable to use a covering material or coating which is substantially a non-conductor of electricity and which will satisfactorily withstand the bombardment set up by the high voltage current passing through the tube. I have found that a coating containing the following constituents has proven very satisfactory. The coating employed is preferably a synthetic resin base enamel in which the pigment consists of titanium and antimony oxide to the extent of about 25.5% by weight of the mixture, there being about twice as muchtitanium oxide as antimony oxide. The balance of the mixture is the vehicle of which any synthetic resin may be used in amount of 30% by weight of the mixture and a volatile thinner in an amount of about 43.6% by weight of the mixture. While I have found a coating of the above composition to be entirely satisfactory, coatings may be utilized having pigment oxides to the extent of from 20% to 30% of the composition with the balance synthetic resins and thinner. The coating may be applied by dipping the sign into the composition and either air dried or baked on under a This type of application I have found produces a substantially uniform coating and therefore a uniform diffusion of the colored light emanating from the luminescent gas. The coating may be applied with a brush, but great care must be taken to assure uniformity of coating to insure proper diffusion of the light.

Figure 3 illustrates a form of coating for the glass tube ID in which the coating material 25 is a suitable color bearing ceramic which may be applied in fluid form and hardened under heat. While this form of the invention may be slightly more expensive to manufacture, the hard ceramic material makes an exceptionally durable surface. I have found the following composition of ceramic coating, which may be baked, fired or fused to an ordinary transparent glass tube at a temperature of around 1000 F. to 1500 F., a coating which will stand severe weather conditions. Particularly because of the fusion, it forms a glazed coating which is substantially as weather resistant as the glass itself. A suitable ceramic fusible glass enamel preferably-including as constituents molybdic acid, a low lead flux, lead molybdate, and a suitable ceramic color oxide and any well known carrier as, for example, alcohol,,turpentine, and the like will give a very satisfactory and uniform coating. The fusible coating may be applied to the glass tubing by immersing the tubing in the ceramic composition or by spraying the composition on the tubing. This coating may be applied to inexpensive glass tubing as, for example, clear lead glass tubing in straightlengths or may be applied to such type of tubing afterit is bent to a sign configuration. I have found that the glass tubing to which the ceramic coating has been applied may be heated in a suitable flame and bent to sign configuration without materially interfering with the fused ceramic coating.

I have found thefollowing method to be en tirely satisfactory in forming a sign of this character wherein the glass tube is formed to a sign configuration. After the letters of the sign or other characters are formed, a suitable hollow tube preferably of glass called a tabulation connection (not shown in the drawing) is connected to a portion of the sign tube preferably to a portion which does not form a part of the luminous sign. The ceramic material is then applied to the portion of the sign which will be rendered luminous by the current conducting gas and the sign placed in a suitable oven and heated to a temperature to fuse or fire the ceramic material to the glass, a temperature of around 1000 F. to 1500 F. for a period of about six minutes being satisfactory to form this function. The electrodes may then be sealed in the ends of the sign tube and the sign tube connected to a vacuum pump by means of the tubulation coupling mentioned above, the vacuum pump operated to withdraw as much. of the'air from the tube as is possible with a pump. A current of high tension is then applied to the electrodes to heat the tube simultaneously with the introduction into the sign tube of the proper amount of the rare gas such as neon, helium, and the like, which is to be rendered luminous for sign purposes. This energization of the tube with current at the time the rare gas is injected is for the purpose of burning out all impurities in the tube and is often termed bomba'rdment. The tubulation connection is then sealed off as indicated at 30 in Figure 1 of the drawing, thus completing the formation of the finished sign.

In order to provide gaseous discharge tube signs with different color characteristics, it has heretofore been the practice to use different gases. In this connection, argon gasemits a purple color, neon a red color, and helium a pinkish white color. With my invention of covering the effective sign portion of the tube with a' large degree the use of different kinds of gases when a change in color is desired.

After considerable test and experimentation, I have found that the sign produced in accordance with my present invention wherein the luminescent portion of the envelope is surrounded with a light diffusing colored covering produces a distinctive sign indication, the visibility of which far surpasses any sign produced such as, for example; those in which the rear portions of the tube are provided with reflective surfaces or partially coated with reflective material, or in which separate reflectors are used adjacent the rear of gaseous tube signs. The sign following my present invention appears to give to the eye of an observer the impression that the entire envelope is a full source of illumination and appears to glow as such, imparting a material contrast to the surrounding medium and is understandably visible from great distances.

A fairly satisfactory result of light diflusing arrangement may. be secured by coating the front half or forward visual portion of the tube structure of the sign, as such partial coating has been found to give a fairly satisfactory light difiusing characteristic. It is to be understood that my ingreat distances and which gives a day time indie,

cation without the necessity of rendering the gas luminous by the passage of current. 4

I have also found that it is entirely practical to apply an opaque coating of a'ceramic enamel upon the cross-overs, bend-backs, or the non-indicating portion of the sign, such as shown at E2 in Figure 1 and the bend-backs or connectors 13 and It, which may also be fired, fused or baked' to the tube. This opaque coating for cross-overs and the like may be applied over the colored ceramic coating for the sign proper after such colored coating has been applied and fused.

It is apparent that within the scope of the invention modfications and difierent arrangements may be made other than is herein disclosed, and the present disclosure is illustrative merely, the invention comprehending all variations thereof.

What I claim is: e

1. The method of forming a luminous gas sign},

which consists in forming a glass tube to a predetermined sign configuration; of coating the sign predetermined sign configuration to a closed member of light transmitting material; coating the outer surface of said member with a suitable pigment having light diffusing characteristics; subjecting the envelope and coating to a temperature to bond said coating to said envelope by mutual fusion of said member and said coating; and filling the envelope with a gas rendered luminescent by the passage of electric current.

3. The method of forming a luminous gas sign, which consists in forming a glass tube to a predetermined configuration; of applying a ceramic colored enamel to portions of said tube; of applying heat to cause the ceramic enamel and the glass tube to become joined by mutual fusion; of withdrawing the air from the tube of filling the tube with a. gas which gives a luminous colored glow different than that of the coating under a passage of electric current; of bo'mbarding the tube with an electric current; and of sealing the tube after completionof the bombardment.

4. The method of making a luminous gas tube,

which comprises forming a glass tube to a desired configuration, applying a ceramic light transmitting enamel to portions of said tube, applying heat to cause the ceramic enamel and the glass tube to become joined by mutual fusion, and in any desired order with respect to applying said light-transmitting enamel applying and fusing an opaquing ceramic enamel to portions ofthe tube where light-transmission is not desired.

5. The method of making a luminous gas tube, wln'ch comprises forming a glass tube to a predetermined configuration, applying an opaquing ceramic enamel to portions of the tube where light transmission is not desired, applying heat to cause the ceramic enamel and the glass tube to become joined by mutual fusion, withdrawing the air from the tube, filling the tube with a gas which is luminous under passage of electric cur-' rent, bombarding the tube with an electric current, and sealing the tube after completion of the bombardment.

CARL R. RUSE. 

